During commercial aircraft flights, meals and beverages are typically offered to the passengers at various times during the flight. For example, German Patent Laying-Open Publication 4,302,706 and corresponding U.S. Pat. No. 5,496,000 (Mueller) disclose a passenger meal service system in which previously prepared and individually portioned meals are stored and then served to the passengers in individual menu service boxes at specified meal times. In contrast, various beverages are offered and served to the passengers as and whenever requested by the passengers. As a result, the number of drinking glasses and cups required during a flight is relatively high, and a corresponding supply of drinking glasses and cups must be kept onboard the aircraft.
Recently, the drinking cups and glasses used onboard aircraft have been disposable or recyclable, but in order to reduce the quantity of garbage, waste or recycling needs, and corresponding storage space onboard the aircraft, efforts are being made to use dishes and cutlery and particularly drinking glasses and cups onboard aircraft, especially during long distance flights. However, since the passengers are served beverages several times during a long flight, a great number of glasses and cups are required, and it is very costly and uneconomical, for logistic and space reasons, to provide reusable cups and glasses that are only used once during a flight and then need to be stored for later cleaning.
For the above reason, it would be desirable to provide an apparatus that cleans or washes the used cups and glasses and other dishes and cutlery onboard the aircraft, so that they may be reused for another meal or beverage service during the same flight. Previously, the use of automatic dish washing machines onboard aircraft has been avoided, because compact and economical apparatus of this type were not available, and because the additional handling and further work effort needed for carrying out such cleaning of the dishes would be very great. For example, each individual item of cutlery, dishes and glassware would have to be removed from the passenger service trays, sorted, loaded into a dish washing machine, removed from the dish washing machine after the washing process, and then again sorted into passenger service trays in passenger service trolleys or the like. Such a procedure would be very costly and time consuming in terms of the time and handling effort required of the flight attendant crew and also the space that must be provided for the washing machines and for carrying out the various steps of the process. German Patent Laying-Open Publication 4,215,614 describes a method and an apparatus for cleaning food service trolleys or carts that are used for transporting food service trays or the like. In order to clean the trolleys, the trays are first removed therefrom, and the trolleys are pushed into a washing chamber equipped with a closeable door, water spray nozzles, a recirculating pump, filters, hot air nozzles, and the like. The trolleys rotate on a platform so that cleaning water jets and then drying air jets can be sprayed into the open side of the trolleys. Also disclosed is a special semicircular wheeled rack for carrying food service trays, so that the rack, loaded with trays, can be wheeled into the washing chamber in order to wash the trays. Disadvantageously, separate manual operations are necessary for removing the trays from the food service trolleys, loading the trays into the washing racks, and separately washing the trolleys and the trays. In other words, cleaning the inside of the trolleys is a separate procedure from cleaning the food service trays that are normally stored in the food service trolleys.
German Patent Laying-Open Publication 3,828,035 describes a method and an apparatus for cleaning food service trolleys and the like, in which the trolleys are loaded onto a conveyor belt which moves the trolleys through various pre-washing, washing, rinsing, and drying stations. Disadvantageously, the known system requires a large amount of floor space and has a high total weight, and also requires a great capital investment, so that the installation and use of such a system in an aircraft is not feasible.
International PCT Publication WO 96/01584 describes a method of preparing and distributing individually portioned meals, as well as a basket and a cutlery holder for carrying out the method. The known method involves bringing dirty dishes and cutlery from an aircraft to a central station at an airport, where the dishes and cutlery are sorted, placed into baskets, sent to an industrial dishwasher where the dishes and cutlery are cleaned, and then returned to a flight kitchen station where meals are prepared using the cleaned dishes and cutlery, whereupon the prepared meals are packed into service trolleys which are then transported to and stored in the aircraft, to be served to passengers in flight.
German Patent Laying-Open Publication 4,330,395 describes a washing machine, and especially a dish washing machine, which includes a used-water tank for storing the used wash water to later be secondarily used for flushing toilets or the like.